What are the types of modified polyimide?

Many specialty materials require the use of bonded polyimide films. Just like some materials have static electricity, it is difficult for ordinary tape to adapt to this situation, but polyimide can be used on it very well, which plays a good role in guaranteeing the performance of special materials. Therefore, in more cases, other tapes are just ordinary, and it is difficult to achieve the purpose of professional use.

Not only to adapt to the electrostatic environment, but also to be fully used in industry, the tape must have strong insulation, which is the primary requirement. Polyimide tape also has good insulating properties, which is the ultimate reason why it is suitable for use here. Another point is to have strong firmness and adapt to the above tapes, which are generally electronic products, and electronic products must ensure long-term performance.

Thermosetting polyimides are low molecular weight polyimides with reactive Mars groups (vinyl, ethynyl, etc.) at both ends of the molecule. In the presence of heat or curing agents, they form macromolecular structures through reactive ridge cleavage cross-linking reactions. There are three commonly used: sodium-terminated polyimide; acetylene-terminated polyimide; maleic anhydride-terminated polyimide; 1. Sodium-terminated polyimide varieties: p105ac, p13n, larc- 13 PMR-Ⅱ, larc-160 and other brands; 2. Acetylene-terminated polyimide has outstanding heat resistance, and the maximum continuous use temperature is 300-370 °C; 3. Maleic anhydride-terminated polyimide, this Polyimide also became bismaleic anhydride, or BMI for short. It is a low molecular weight compound with maleimide as active end group.

It is derived from the condensation of diamine and maleic anhydride. Advantages: highly reactive double bonds. It can be homo- or co-polymeric. The curing reaction is an addition reaction, and there is no precipitation of low-molecular-weight substances.

The cured product has the characteristics of high temperature resistance, humidity resistance and radiation resistance. It also has high modulus, high strength and intentional electrical insulation. Disadvantages: some, such as bismaleic anhydride, are brittle and not applicable in some fields.

There are three types of modified polyimides: polyetherimide, polyesterimide and polyamideimide. Polyetherimide Polyimide is an amber transparent thermoplastic. Its molecular structural formula is: due to the introduction of a flexible ether bond and an isopropyl group into the molecule, the melt fluidity of the polyetherimide is greatly improved. It can be processed by common thermoplastic processing methods such as injection molding, extrusion and thermoforming. Polyamideimide polyesterimide has the electrical properties, mechanical properties, heat resistance, solvent resistance, radiation resistance and processing properties of aromatic polyesters. It can be injected, extruded and pressed. It has good dimensional stability and low cost.